High-temperature press-in stress relaxation test system

Abstract

The invention provides a high-temperature press-in stress relaxation testing system, which belongs to the field of material high-temperature mechanical property testing and comprises a press-in system, a measuring system, a heating system, a fixing frame, an environment adjusting system and a data acquisition system. According to the equipment, constant deformation is applied through a press-in method under the high-temperature condition, the stress relaxation behavior of a material under the high-temperature condition is monitored in real time, and the environment temperature is adjusted by adopting an environment adjusting system so as to ensure the stability of a test environment. According to the method, the high-temperature stress relaxation performance of the micro sample can be evaluated, the restriction of component size and structural factors is avoided, a reference is provided for high-temperature performance evaluation of components with complicated structures or small sizes, and accurate control of the high-temperature performance of real service components is facilitated.

Description

Technical Field

[0001] The invention belongs to the field of high-temperature mechanical property testing of materials, and relates to a device for measuring high-temperature stress relaxation performance of materials by an indentation method, wherein an environmental adjustment system is integrated to ensure the stability of the testing process and the measurement accuracy. Background Art

[0002] Under high temperature and load, equipment in the fields of petroleum, chemical, navigation and aerospace will experience stress relaxation problems, resulting in problems with structural fastening and matching, thus affecting the performance and service life of the equipment. Understanding the stress relaxation behavior of materials plays a key role in the material design and service life of key components in the fields of aerospace, energy, nuclear power, etc. Traditional stress relaxation test methods mostly use tensile tests, which require larger sample sizes and are difficult to sample and analyze for existing small-sized or special structural components.

[0003] In order to solve the testing difficulties of components with limited size or complex structure, the press-in method has gradually been applied to the mechanical property testing of materials, and the corresponding national standards have been formed. Compared with the traditional tensile test method, the press-in method has the advantages of small sample size requirements, simple sample preparation and convenient operation. However, the stability and accuracy of the press-in method equipment under high temperature conditions are still challenging. Therefore, the present invention optimizes the overall performance of the press-in method for measuring high-temperature stress relaxation equipment by adding an environmental adjustment function. Summary of the invention

[0004] The present invention provides a device for measuring high temperature stress relaxation performance by using a press-in method. The purpose of the present invention is to provide a device for measuring high temperature stress relaxation performance of a material by using a press-in test method, so as to solve the problems of test accuracy and stability of high temperature test equipment in the prior art. The present invention achieves accurate and stable measurement of stress relaxation performance of materials under high temperature conditions by optimizing the structural design and system of the press-in test equipment.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A high-temperature press-in relaxation test system includes six parts: a press-in system, a measuring system, a heating system, a fixed frame, an environmental adjustment system, and a data acquisition system. The high-temperature press-in relaxation test system accurately controls the sample temperature through the heating system to ensure temperature stability. The environmental adjustment system introduces inert gas to prevent oxidation of the sample surface, and self-adjusts the temperature of the upper and lower high-temperature press rods and the deformation lead-out rod to reduce the interference of external environmental fluctuations on the experimental results. After the sample reaches the set temperature and is kept constant for a period of time, the press-in system begins to load until the preset press-in amount is reached and remains constant. During the test, the data acquisition system and the measuring system work together to monitor the changes in the force and press-in amount generated by the press-in system in real time, and perform feedback adjustment to ensure the stability of the test environment and the accuracy of the output data. The system automatically records the data of the entire test process and generates data curves for subsequent analysis. The fixed frame provides reliable structural support for the entire system to ensure the smooth development of the test. The details are as follows:

[0007] Pressing system: A controllable pressing load is applied by a precision servo motor to press a high-strength and high-temperature resistant pressing head into the specimen to provide stress or strain conditions for stress relaxation tests. It includes a servo motor 1, a reducer 2, an electric cylinder 3, an upper high-temperature pressing rod 4, a pressing head 5, a pressing plate 6 and a lower high-temperature pressing rod 7. Specifically: The high-speed rotation of the servo motor 1 increases the torque through the reducer 2, and converts the increased torque into the linear motion of the upper high-temperature pressing rod 4 through the electric cylinder 3, thereby driving the pressing head 5 to descend and press into or rise and leave the specimen; the specimen is placed on the pressing plate 6, and the pressing plate 6 is installed on the upper end of the lower high-temperature pressing rod 7 to provide support for the specimen; the lower end of the lower high-temperature pressing rod 7 is connected to the load sensor in the measurement system to achieve responsible detection and control.

[0008] Measuring system: Use high-precision force sensors (accuracy 0.05N ~ 0.1N) and high-precision micrometer sensors (accuracy 0.00002mm ~ 0.00005mm) to monitor the load and deformation in real time to ensure that the pressing system maintains a constant pressing amount. It includes a deformation lead-out rod 8, a micrometer sensor 9 and a load sensor 10. Specifically: The deformation lead-out rod 8 is connected to the pressure head 5, and the downward and upward movement of the pressure head 5 is transmitted to the micrometer sensor 9, which is used to accurately measure the movement of the pressure head 5. At the same time, the load sensor 10 is fixed at the lower end of the lower high-temperature pressure rod 7 to monitor the load condition.

[0009] Heating system: A high-precision temperature control device is used to heat the environment of the sample to a preset temperature and maintain a constant high-temperature environment. The temperature range is usually between 500°C and 1200°C, and the control accuracy is 0.05°C to 0.1°C. It includes a high-temperature furnace 11, a temperature sensor 12, and a high-temperature furnace arm 13. Specifically: The high-temperature furnace 11 is fixed on the high-temperature furnace bend wall 13 to provide a stable heat source for the test space; the high-temperature furnace bend wall 13 is installed on the column 17 of the fixed frame to ensure that the heating system has a stable structural support. At the same time, three temperature sensors 12 are respectively extended into the high-temperature furnace 11, connected to the pressure head 5, the sample and the pressure plate 6, to monitor the temperature of these three key parts in real time to ensure the temperature stability in the test space.

[0010] Fixed frame: This structure provides a stable support structure for other systems, which can ensure the stability of the measurement system and the firm and safe installation of other systems. It includes adjustable feet 14, base box 15, table 16, column 17, beam 18, beam fixing nut 19 and motor fixing bolt 20. Specifically: adjustable feet 14 are installed under the base box 15 to adjust the level of the experimental device; micrometer sensor 9 and load sensor 10 are placed inside the base box 15 to provide protection for them; the upper surface of the base box 15 is the table 16 for experimental personnel to perform experimental operations; the column 17 is fixed on both sides of the table 16 to provide stable structural support for the pressing system and the heating system; the beam 18 is located at the upper end of the column 17 and is fixed by the beam fixing nut 19; the motor fixing bolt 20 fixes the servo motor 1, reducer 2 and electric cylinder 3 to the upper surface of the beam 18 to ensure their stable operation.

[0011] Environmental regulation system: On the one hand, by delivering inert gas (such as argon or nitrogen) to the test area, gas protection is formed to prevent high-temperature oxidation of the pressure head and the material; on the other hand, the structural temperature fluctuation of the pressure-in system and the measurement system is reduced through a simple structure, interference is reduced and data accuracy is improved. It includes a gas cylinder 21, a pressure reducing valve 22, an air guide pipe 23, a lower heat stabilizer 24 and an upper heat stabilizer 25. Specifically: the inert gas is stored in the gas cylinder 21, the outlet pressure is controlled by the pressure reducing valve 22, and is introduced into the lower end of the lower heat stabilizer 24 through the air guide pipe 23; with the help of the rising effect of hot air, the inert gas enters the interior of the heating furnace to protect the sample from oxidation; the lower heat stabilizer 24 is connected to the lower end surface of the heating furnace, and through the space shielding effect, it blocks the influence of the external environment on the lower high-temperature pressure rod 17 and the deformation lead-out rod 18; the upper heat stabilizer 25 is connected to the upper high-temperature pressure rod 4 to buffer the influence of the external environment on the upper high-temperature pressure rod.

[0012] The lower heat stabilizer 24 is a cylindrical structure, with the upper end fixed to the lower end surface of the high-temperature furnace 14 and the lower end suspended in the air, 2-10 cm away from the table 16, and surrounding the outer side of the lower high-temperature pressure rod 7 and the deformable lead-out rod 18. The lower heat stabilizer 24 is a split design, and can be opened and closed together with the high-temperature furnace 11. The lower heat stabilizer 24 forms a heat barrier layer around the lower high-temperature pressure rod 7 through the heat radiation of the high-temperature furnace 11, effectively blocking the temperature impact of the external environment on the lower high-temperature pressure rod 7 and the deformable lead-out rod 18, so as to ensure the length stability of the lower high-temperature pressure rod 7 and the deformable lead-out rod 18. The lower heat stabilizer 24 can be a split cylindrical shape (such as Figure 2 It can also be designed into other suitable shapes to meet different appearance requirements.

[0013] The upper heat stabilizer 25 is a cylindrical structure, with the upper end fixed on the upper high-temperature pressure rod 4 and the lower end suspended in the air, 1-5 cm away from the upper end surface of the high-temperature furnace 11. The upper heat stabilizer 25 uses the rising hot air flow generated by the high-temperature furnace 11 to form a heat barrier around the upper high-temperature pressure rod 4, thereby effectively blocking the influence of external environmental disturbances on the upper high-temperature pressure rod 4 and ensuring the length stability of the upper high-temperature pressure rod 4. The upper heat stabilizer 25 can be a split cylindrical structure (such as Figure 3 It can also be designed into other suitable shapes to meet different appearance requirements.

[0014] Data acquisition and analysis system: using adjustable frequency (10 -5 HZ~10 2 HZ) data acquisition card and analysis software are used to record, screen and process the data generated during the test, and generate stress-time curves, deformation-time curves and deformation-rate curves, etc. It includes a temperature signal collector 26, a load and deformation signal collector 27 and a display terminal 28. Specifically: the temperature signal collector 26 is connected to the heating system to collect the temperature signal of the temperature sensor 12, and adjust the heating power of the high-temperature furnace 11 according to the feedback to ensure the stability of the temperature; the load and deformation signal collector 27 is connected to the pressing system and the measuring system, on the one hand, it collects the load signal of the load sensor 10 and the deformation signal of the micrometer sensor 9, and on the other hand, it controls the rotation of the servo motor 1 to achieve precise control of the pressing process; finally, all the collected signals are displayed and output through the display terminal 28 for real-time monitoring and data analysis by the experimenters.

[0015] The beneficial effects of the present invention are:

[0016] (1) High-performance pressing and measuring system: The high-hardness, high-temperature-resistant ceramic pressing head and the high-strength upper and lower pressing rods can effectively convert the pressure provided by the servo motor into pressing displacement; the measuring system constantly monitors the changes in pressing displacement, pressing stress and temperature, and adjusts the feedback control system to achieve high-precision pressing control.

[0017] (2) Stable environmental control: The heating system can achieve high-precision temperature control to ensure smaller temperature fluctuations during the test. At the same time, the environmental adjustment system uses inert gas to prevent oxidation or other chemical reactions of the material. The special structural design of the upper and lower thermal stabilizers can adjust the temperature balance of the test system, improve system stability and test accuracy, and ensure the accuracy of the test results.

[0018] (3) Multifunctional adaptability: The equipment is suitable for a variety of materials and test environments. By flexibly adjusting the test conditions, it can adapt to various complex test requirements and is used for testing and analysis of high-temperature material properties in laboratories and industries.

[0019] (4) Automated data acquisition and analysis: The equipment can record stress relaxation data in real time and generate complete stress relaxation curves to help users quickly analyze material properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of a high-temperature press-in stress relaxation test system of the present invention.

[0021] In the figure: 1 servo motor, 2 reducer, 3 electric cylinder, 4 upper high-temperature pressure rod, 5 pressure head, 6 pressure plate, 7 lower high-temperature pressure rod, 8 deformation lead-out rod, 9 micrometer sensor, 10 load sensor, 11 high-temperature furnace, 12 temperature sensor, 13 high-temperature furnace crank arm, 14 adjustable foot, 15 base box, 16 table, 17 column, 18 beam, 19 beam fixing nut, 20 motor fixing bolt, 21 gas cylinder, 22 pressure reducing valve, 23 air guide tube, 24 lower heat stabilizer, 25 upper heat stabilizer, 26 temperature signal collector, 27 load and deformation signal collector and 28 display terminal.

[0022] Figure 2 It is a schematic diagram of the lower heat stabilizer in the present invention.

[0023] Figure 3 It is a schematic diagram of the upper heat stabilizer in the present invention.

[0024] Figure 4 The relationship between deformation and time of the stress relaxation test with a compression of 0.05 mm carried out at 750°C in the present invention.

[0025] Figure 5 This is a stress relaxation curve of the stress relaxation test carried out at 750°C with a compression of 0.05 mm in the present invention. DETAILED DESCRIPTION

[0026] The following describes the implementation of the present invention in detail with reference to the accompanying drawings and technical solutions.

[0027] Figure 1Schematic diagram of the system for testing the high temperature stress relaxation performance of materials by the press-in method of the present invention. The device of this embodiment mainly includes: a press-in system (servo motor 1, reducer 2, electric cylinder 3, upper high temperature pressure rod 4, pressure head 5, pressure plate 6 and lower high temperature pressure rod 7), a measuring system (deformation lead-out rod 8, micrometer sensor 9 and load sensor 10), a heating system (high temperature furnace 11, temperature sensor 12 and high temperature furnace crank arm 13), a fixed frame (adjustable foot 14, base box 15, table 16, column 17, beam 18, beam fixing nut 19 and motor fixing bolt 20), an environmental adjustment system (gas cylinder 21, pressure reducing valve 22, air guide pipe 23, lower heat stabilizer 24 (such as Figure 2 As shown), upper heat stabilizer 25 (as Figure 3 As shown)) and the data acquisition and analysis system (temperature signal collector 26, load and deformation signal collector 27 and display terminal 28) are a total of six parts.

[0028] The following is an example of the stress relaxation test of Sanicro25 heat-resistant steel:

[0029] First, the sample is placed on the pressing plate 6, and the inert gas is released from the gas cylinder 21. After the inert gas is decompressed by the pressure reducing valve 22, it enters the lower end of the lower heat stabilizer 24 through the gas guide pipe 23. During the experiment, the inert gas will rise with the increase of temperature and enter the interior of the high-temperature furnace 11 to form a protective atmosphere to prevent the sample from being oxidized at high temperature.

[0030] Next, the high temperature furnace 11 is started to heat the sample to 750° C. The temperature signal collector 26 collects the temperature signal from the temperature sensor 12 and feedback controls the heating power of the high temperature furnace 11 to ensure accurate temperature control.

[0031] Third, after the sample is kept constant at 750℃ for 0.5-2h, the internal temperature of the lower heat stabilizer 24 and the upper heat stabilizer 25 reaches a balanced state, and the pressing system starts to load. The high-speed rotation of the servo motor 1 increases the torque through the reducer 2, and then converts it into the linear motion of the upper high-temperature pressing rod 4 through the electric cylinder 3, thereby driving the pressing head 5 to press down into the sample until the downward pressure reaches 0.05mm. The lower high-temperature pressing rod 7 provides sufficient support for the sample to ensure the stable force balance during the test.

[0032] Fourth, when the pressing amount reaches 0.05 mm, the pressing amount is kept constant until the end of the test. During the test, the load and deformation signal collector 27 collects the load signal of the load sensor 10 and the deformation signal of the micrometer sensor 9, and performs feedback control and data output in real time. All collected signals are displayed through the display terminal 28 for monitoring and post-processing by the experimenter.

[0033] During the stress relaxation process, the pressure changes with time as follows: Figure 4As shown in the figure, the stress relaxation curve (i.e. the load-time curve) is as follows Figure 5 The test results show that the experiment meets the test requirements and the data meets the needs of subsequent analysis.

[0034] The above-described embodiments merely express the implementation methods of the present invention, but they cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A high temperature press-in stress relaxation test system, characterized in that: The high-temperature press-in stress relaxation test system includes six parts: a press-in system, a measuring system, a heating system, a fixed frame, an environmental adjustment system and a data acquisition system; the high-temperature press-in relaxation test system accurately controls the sample temperature through the heating system; the environmental adjustment system introduces inert gas and self-adjusts the temperature of the upper and lower high-temperature press rods and the deformation lead-out rod; after the sample reaches the set temperature and is kept constant, the press-in system starts loading until the preset press-in amount is reached and remains constant; during the test, the data acquisition system and the measuring system work together to monitor the changes in the force value and press-in amount generated by the press-in system in real time, and perform feedback adjustment; the system automatically records the data of the entire test process and generates a data curve for subsequent analysis; the fixed frame provides structural support for the entire system.

2. A high temperature press-in stress relaxation test system according to claim 1, characterized in that: The pressing system comprises a servo motor (1), a reducer (2), an electric cylinder (3), an upper high-temperature pressing rod (4), a pressing head (5), a pressing plate (6) and a lower high-temperature pressing rod (7). A controllable pressing load is applied by the servo motor (1) to press the high-strength and high-temperature resistant pressing head into the sample, thereby providing stress or strain conditions for the stress relaxation test. Specifically: The high-speed rotation of the servo motor (1) increases the torque through the reducer (2), and converts the increased torque into the linear motion of the upper high-temperature pressure rod (4) through the electric cylinder (3), driving the pressure head (5) to descend and press into or ascend and leave the sample; the sample is placed on the pressure plate (6), and the pressure plate (6) is installed on the upper end of the lower high-temperature pressure rod (7); the lower end of the lower high-temperature pressure rod (7) is connected to the load sensor in the measurement system.

3. A high temperature press-in stress relaxation test system according to claim 2, characterized in that: The measuring system comprises a deformation lead-out rod (8), a micrometer sensor (9) and a load sensor (10), which can monitor the load and deformation in real time to ensure that the pressing system maintains a constant pressing amount. Specifically: The deformation lead-out rod (8) is connected to the pressure head (5) to transmit the downward and upward movement of the pressure head (5) to the micrometer sensor (9) for accurately measuring the movement of the pressure head (5); at the same time, the load sensor (10) is fixed at the lower end of the lower high-temperature pressure rod (7) to monitor the load condition.

4. A high temperature press-in stress relaxation test system according to claim 3, characterized in that: The heating system comprises a high temperature furnace (11), a temperature sensor (12) and a high temperature furnace arm (13), and adopts a high-precision temperature control device to heat the environment of the sample to a preset temperature and maintain a constant high temperature environment, wherein the temperature range is 500°C to 1(20)0°C, and the control accuracy is 0.05°C to 0.1°C; specifically: The high temperature furnace (11) is fixed on the high temperature furnace bend wall (13), and the high temperature furnace bend wall (13) is installed on the column (17) of the fixed frame. Three temperature sensors (12) are respectively extended into the high temperature furnace (11), and are connected to the pressure head (5), the sample and the pressure plate (6), so as to monitor the temperature of these three key parts in real time and ensure the temperature stability in the test space.

5. A high temperature press-in stress relaxation test system according to claim 4, characterized in that: The fixed frame includes adjustable feet (14), a base box (15), a table top (16), columns (17), and a crossbeam (18), specifically: An adjustable foot (14) is installed below the base box (15); a micrometer sensor (9) and a load sensor (10) are placed inside the base box (15); the upper surface of the base box (15) is a table top (16); columns (17) are fixed on both sides of the table top (16); a crossbeam (18) is located at the upper end of the column (17) and is fixed by a crossbeam fixing nut (19); a motor fixing bolt (20) fixes the servo motor (1), the reducer (2) and the electric cylinder (3) to the upper surface of the crossbeam (18).

6. A high temperature press-in stress relaxation test system according to claim 5, characterized in that: The environmental adjustment system comprises a gas cylinder (21), a pressure reducing valve (22), an air guide tube (23), a lower heat stabilizer (24) and an upper heat stabilizer (25), and is used to transport inert gas to the test area to prevent high-temperature oxidation of the pressure head and the material, and reduce structural temperature fluctuations of the pressure injection system and the measurement system; specifically: The inert gas is stored in a gas cylinder (21), the outlet pressure of which is controlled by a pressure reducing valve (22), and is introduced into the lower end of a lower heat stabilizer (24) via an air guide pipe (23); the inert gas enters the interior of the heating furnace; the lower heat stabilizer (24) is connected to the lower end surface of the heating furnace to block the influence of the external environment on the lower high-temperature pressure rod (17) and the deformation lead-out rod (18); the upper heat stabilizer (25) is connected to the upper high-temperature pressure rod (4) to buffer the influence of the external environment on the upper high-temperature pressure rod.

7. A high temperature press-in stress relaxation test system according to claim 6, characterized in that: The specific structures of the lower heat stabilizer (24) and the upper heat stabilizer (25) are as follows: The lower heat stabilizer (24) is a cylindrical structure, the upper end of which is fixed to the lower end surface of the high-temperature furnace (14), and the lower end is suspended in the air, at a certain distance from the table (16), and surrounds the outer side of the lower high-temperature pressure rod (7) and the deformation lead-out rod (18); the lower heat stabilizer (24) is a split design, and can be opened and closed together with the high-temperature furnace (11); the lower heat stabilizer (24) forms a heat barrier layer around the lower high-temperature pressure rod (7) through the heat radiation of the high-temperature furnace (11), thereby ensuring the length stability of the lower high-temperature pressure rod (7) and the deformation lead-out rod (18); The upper heat stabilizer (25) is a cylindrical structure, the upper end of which is fixed on the upper high-temperature pressure rod (4), and the lower end is suspended in the air and is a certain distance away from the upper end surface of the high-temperature furnace (11); the upper heat stabilizer (25) uses the rising hot air flow generated by the high-temperature furnace (11) to form a heat barrier layer around the upper high-temperature pressure rod (4), thereby ensuring the length stability of the upper high-temperature pressure rod (4).

8. A high temperature press-in stress relaxation test system according to claim 7, characterized in that: The lower end surface of the lower heat stabilizer (24) is 2-10 cm away from the table top (16); the lower end surface of the upper heat stabilizer (25) is 1-5 cm away from the upper end surface of the high-temperature furnace (11).

9. A high temperature press-in stress relaxation test system according to claim 6, characterized in that: The data acquisition and analysis system comprises a temperature signal collector (26), a load and deformation signal collector (27) and a display terminal (28), and is used to generate a stress-time curve, a deformation-time curve, a deformation-rate curve, etc. Specifically: The temperature signal collector (26) is connected to the heating system and is used to collect the temperature signal of the temperature sensor (12) and adjust the heating power of the high-temperature furnace (11) according to the feedback; the load and deformation signal collector (27) is connected to the pressing system and the measuring system, collects the load signal of the load sensor (10) and the deformation signal of the micrometer sensor (9), controls the rotation of the servo motor (1), and realizes precise control of the pressing process; all collected signals are displayed and output through the display terminal (28).

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